Sometime ago I was on BA9 en-route to KUL when the engines went off all at the same time.

Apparently it was some sort of ash cloud or so that was what the crew said it was. I'm not absolutely sure to be honest.

Anyway, the aircraft landed somewhere in Indonesia with no engines. Apparently we had to glide all the way there which only made the delay worse and they stopped serving drinks and made us put on those ghastly yellow jackets.

The flight eventually got cancelled. So, do you think I can retroactively claim compensation under EU261/2004 despite this happening in 1982?

I don't think this can be called "exceptional circumstances" surely?